If it takes 30 seconds for a sample of O₂ gas to effuse through a porous plug, how long will it take for an equal amount of N₂ gas to escape through the same plug?

Question

Quizplus · Accepted Answer

The rate of effusion is inversely proportional to the square root of the molar mass of the gas (Graham's Law of Effusion). Let's denote the rate of effusion of the O₂ gas as R1 and the rate of effusion of the N₂ gas as R2. According to Graham's Law of Effusion: R1/R2= sqrt(M2/M1) where M1 and M2 are the molar masses of O₂ and N₂, respectively. The two gases are isomers, so they have the same molar mass. Therefore, M1=M2 and R1/R2=1. This means that the rates of effusion of the two gases are equal. Since it takes 30 seconds for the O₂ gas to effuse through the porous plug, it will take the same amount of time for the N₂ gas to effuse through the same plug. Therefore, the answer is C) 28.1 sec.

If It Takes 30 Seconds for a Sample of O2

If It Takes 30 Seconds for a Sample of O₂